1. Field of the Invention
This application relates to an apparatus for recording and reading an image, and more particularly, to such apparatus which is adapted to record and read a multicolor image.
2. Description of the Prior Art
In optical digital data recording, the recording medium can be a major contributor to signal errors. Missing or spurious signals induced by media defects cause data loss or contamination of the recorded information. Consequently, error detection and correction (EDAC) capability is incorporated into recording and playback systems. Such capability is usually in the form of software programs to encode and decode signals. During the recording phase, redundancy is built in by signal coding. During playback, the signal is verified or corrected by a deciphering code.
The proportion of a recording medium which is dedicated to error correction can be significant; for example, thirty percent is not unusual. Higher redundancy is required if the medium is imperfect, or if a very low error content is needed. Bit error rates of one in 10.sup.13 or less are sought in some applications. With present technology, optical media can not be manufactured to that degree of perfection.
The cost of EDAC is high not only in terms of the data storage density but also in terms of the data processing time and the complexity of the recording and decoding devices. Clearly, a system which can discriminate between recorded data and media defects offers an advantage. The benefits of such a system would include lower bit error rates and less redundancy which would result in higher data storage density.